Low fuel sensors use NTC thermistors using the same components except the ground is grounded in a metal can welded to the fuel sender held stationary (example; 12mm X 12mm round) wrapped in foil to transfer heat. A single wire completes the circuit at the dash or instrument panel. Changing fuel pumps (Top referencing and Bottom referencing) types. I took these apart as they had holes in the bottom only. Once fuel levels dropped exposing the thermistor little by little until they allowed enough current to full saturation of the transistor to complete the LED circuit, turning it on. This is why many came on dim during turns and other low fuel condition. The foil transfers heat but when empty, low current at the NTC thermistor doesn't produce heat to feel in your fingers. Plus, out of gas? Most vehicles still have 2 - 3 gallons in reserve on their way to the gas station. ASE Master Tech since 78, retired.
Can you tell the value or specification of the NTC? I search online store and says something like 5D- 15 , 10D-25, etc. So I don't know which one to pick.
Hi. The reason for using two transistors here is to provide a better current gain. The left-hand transistor is triggered by the base current. Then the collector current of this transistor triggers the right transistor. Thus, the LED gives light. I can explain it this way.
nice work
Good
Low fuel sensors use NTC thermistors using the same components except the ground is grounded in a metal can welded to the fuel sender held stationary (example; 12mm X 12mm round) wrapped in foil to transfer heat. A single wire completes the circuit at the dash or instrument panel. Changing fuel pumps (Top referencing and Bottom referencing) types. I took these apart as they had holes in the bottom only. Once fuel levels dropped exposing the thermistor little by little until they allowed enough current to full saturation of the transistor to complete the LED circuit, turning it on. This is why many came on dim during turns and other low fuel condition. The foil transfers heat but when empty, low current at the NTC thermistor doesn't produce heat to feel in your fingers. Plus, out of gas? Most vehicles still have 2 - 3 gallons in reserve on their way to the gas station.
ASE Master Tech since 78, retired.
Can you tell the value or specification of the NTC?
I search online store and says something like 5D- 15 , 10D-25, etc.
So I don't know which one to pick.
our circuit is glowing even without giving it high temperature..what can we do about this?
dear sir, can you make it with mq2 sensor, thank you very much
Sir can i use BC547 instead of BC237 transistor
Hi sir, can you explain the flow of this circuit?
Hi. The reason for using two transistors here is to provide a better current gain. The left-hand transistor is triggered by the base current. Then the collector current of this transistor triggers the right transistor. Thus, the LED gives light. I can explain it this way.
how collector trigger right transistor ? And how ntc trigger left transistor?
Can I use PTC instead of NTC in this circuit?
you will have to freeze the thermistor for led to shine
Pl provides examples on ptc.
🤙
Hi,
how i can modify this circuit for 5V ?
Hello sir only one transistor enough know sir....... Plz reply
Hi. One transistor is also grounded, but it is useful to have two transistors for a better current gain.